Respuesta :

4*((7x-6)+(4x-3))=360

7x-6+4x-3=90

11x=99

x=9

∠ACD = (7x-6)=7*9-6 = 57°

BD is the angle bisector of ∠ADC
Therefore ∠ADC=(8x-6)°

Same for ∠DCB, AC bisects ∠DCB
Therefore ∠DCB=(14x-12)°

Because AD//BC, ∠DCB+∠ADC=180°
i.e. 22x-18=180
x=9